Si8244 SILABS [Silicon Laboratories], Si8244 Datasheet - Page 23

• Manufacturer Part Number: Si8244
• Description: CLASS D AUDIO DRIVER WITH PRECISION DEAD-TIME GENERATOR
• Manufacturer: SILABS [Silicon Laboratories]

4. Applications
The following examples illustrate typical circuit configurations using the Si824x.
4.1. Class D Digital Audio Driver
Figures 38 and 39 show the Si8241/4 controlled by a single PWM signal. Supply can be unipolar (0 to 1500 V) or
bipolar (± 750 V).
D1 and CB form a conventional bootstrap circuit that allows VOA to operate as a high-side driver for Q1, which has
a maximum drain voltage of 1500 V. VOB is connected as a conventional low-side driver. Note that the input side of
the Si824x requires VDD in the range of 4.5 to 5.5 V, while the VDDA and VDDB output side supplies must be
between 6.5 and 24 V with respect to their respective grounds. The boot-strap start up time will depend on the CB
cap chosen. VDD2 is usually the same as VDDB. Also note that the bypass capacitors on the Si824x should be
located as close to the chip as possible. Moreover, it is recommended that 0.1 and 10 µF bypass capacitors be
used to reduce high frequency noise and maximize performance. The D1 diode should be a fast-recovery diode; it
should be able to withstand the maximum high voltage (e.g. 1500 V) and be low-loss. See “AN486: High-Side
Bootstrap Design Using Si823x ISODrivers in Power Delivery Systems” for more details in selecting the bootstrap
cap (CB) and diode (D1).
Figure 38. Si824x in Half-Bridge Audio Application
Figure 39. Si824x in Half-Bridge Audio Application
CONTROLLER
CONTROLLER
PWMOUT
PWMOUT
I/O
I/O
1uF
1uF
C1
C1
VDDI
VDDI
RDT
RDT
VDDI
GNDI
PWM
DT
DISABLE
VDDI
GNDI
PWM
DT
DISABLE
Rev. 0.2
Si8241/4
Si8241/4
GNDA
GNDB
GNDA
GNDB
VDDA
VDDB
VDDA
VDDB
VOA
VOB
VOA
VOB
VDD2
VDD2
VDDB
VDDB
1 µF
10uF
1 µF
10uF
C2
C2
C3
C3
D1
D1
CB
CB
1500 V max
+750 V max
-750 V max
Q2
Q2
Q1
Q1
Si824x
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